Luminescence enhancement effect of Ag@SiO₂ coreshell nanoparticles on Eu-PMMA films

In order to improve the luminescent properties of rare earth ions, precious metal nanoparticles were doped into rare earth luminescent materials. Metal plasma resonance can produce local electric field, which acts on the luminescence process of rare earth ions, and can achieve the luminescence enhancement. Ag@SiO₂ core-shell nanoparticles can effectively control the distance between metal Ag and rare earth ions, which can not only enhance the plasmonic resonance effect, but also avoid the fluorescence quenching caused by non-radiation energy transfer when they are too close to the emission center. Firstly, the Ag@SiO₂ nanoparticles with different concentrations were dropped on the quartz wafers by drop-casting method. Then, the Eu(dbm)₃Phen:PMMA: dichloromethane mixed solution was spin-coated to prepare the Eu-PMMA composite film. The morphology characterization and luminescence measurement of the samples showed that the luminescence intensity of the film doped with Ag@SiO₂ nanoparticles was enhanced, and the maximum enhancement factor of the measured excitation spectrum was 2.50 times, and the maximum enhancement factor of the emission spectrum was 2.15 times. The results of the fluorescence lifetime measurement of the sample indicated that the luminescence lifetime of the film containing Ag@SiO₂ nanoparticles was also prolonged. The doping of Ag@SiO₂ nanoparticles in the rare earth luminescent materials shows a good enhancement, and the experimental method is highly operable. It is a promising method to enhance the luminescent intensity of rare earth luminescent materials.